Overspeed and positioning device for a shaft

ABSTRACT

In certain situations a rotating shaft may rotate too rapidly or be positioned at a precarious angle so as not to be operating in a safe manner. Under these operating conditions it is necessary to control the angular speed of the rotating shaft or to control the angle of the rotating shaft. An example of a shaft rotating too rapidly or being positioned at a precarious angle is one where there is a scaffold, on a building, suspended by cables from the top of the building. The winch or winches for winding and unwinding these cables may be on the suspended scaffold or may be on a carriage on the roof of the building. If the winches unwind too rapidly the scaffold descends too rapidly with possible injury to the people riding the scaffold. Also, if the cables attached to the scaffold assume different lengths, then the angle of the scaffold may be such that the occupants of the scaffold may slide to one end of the scaffold and even slide off the scaffold. This invention is directed to an apparatus and a method for stopping the rotation of a rotating shaft which is rotating too rapidly or for stopping the rotation of a rotating shaft at a precarious angle, on the combination of too rapid a rotation of the rotating shaft and the shaft being at a precarious angle.

United States Patent 1 Brauss OVERSPEED AND POSITIONING DEVICE FOR A SHAFT [76] Inventor: Albert Brauss, 7517-196th Ave.

NE, Redmond, Wash. 98052 22 Filed: Dec. 13, 1971 21 App]. No.: 207,139

Primary Examiner-Reinaldo P. Machado Attorney-Thomas W. Secrest [57] ABSTRACT In certain situations a rotating shaft may rotate too rapidly or be positioned at a precarious angle so as not to be operating in a safe manner.

Under these operating conditions it is necessary to control the angular speed of the rotating shaft or to control the angle of the rotating shaft.

An example of a shaft rotating too rapidly or being positioned at a precarious angle is one where there is a scaffold, on a building, suspended by cables from the top of the building. The winch or winches for winding and unwinding these cables may be on the suspended scaffold or may be on a carriage on the roof of the building.

If the winches unwind too rapidly the scaffold descends too rapidly with possible injury to the people riding the scaffold. Also, if the cables attached to the scaffold assume different lengths, then the angle of the scaffold may be such that the occupants of the scaffold may slide to one end of the scaffold and even slide off the scaffold.

the combination of too rapid a rotation of the rotating shaft and the shaft being at a precarious angle.

49 Claims, 38 Drawing Figures 'PATENTEDBEB 41m 3.776.368

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This invention is directed to controlling the angular velocity of a rotating shaft; to indicate the position of a shaft withrespect to the horizontal and which position may be considered to be at a precarious angle with respect to the horizontal; and, to the combination of controlling the angular velocity of a rotating shaft and the position of the rotating shaft with respect to the horizontal.

An example of the use'of this invention is in regard to a scaffold for maintaining th exterior of a modern building. Many of the modern buildings have a scaffold which is suspended by cables from the roof of the building. Generally speaking, there will be at least two cables. It is possible to have a small scaffold suspended by one cable. However, in most installations the scaffold will be suspendedby two cables of a sufficient strength to support two men for working on the exterior surface of the building. The winches for winding and unwinding these cables may be on the scaffold or may be on a drum on the building. If the scaffold descends too rapidly, it is possible that the workmen will be placed in a position whereby they could be injured. To control the descent of the scaffold, I have invented an overspeed device which can be attached to the shaft of the winch or else be made substantially integral with the shaft of the winch. Then, if the scaffold descends too rapidly,

the overspeed device activates a brake to stop the rapid descent of the scaffold.

Also, if there are two winches on the scaffold and one of the winches does not operate properly, the scaffold will tilt and, in extreme circumstances, assume a substantially vertical position. If there be one or two workmen on the scaffold, it can be readily seen that the workmen'will move to the lower end of the scaffold and may haveto hang on to the scaffold in order to not fall off the scaffold and possibly be injured or killed. It has happened-that a scaffold has tilted so that the longitudinal axis of the scaffold became substantially vertical. In order to save the workmen on the scaffold, it was necessary to call a fire department and to place a net underneath the workmen so that when they let go of the scaffold they would fall into the net and not be hurt.

' braking device on the winch so as to stop the operation of the winch. Therefore, the longitudinal axis of the scaffold does not assume a substantially vertical position but assumes an angle of approximately 45 of less with respect to the horizontal. In this manner a workman, or workmen, on the scaffold are placed in a more safe position.

Further, my invention is applicable both to the combination of controlling the angular velocity of a rotating shaft and also the angular position of the rotating shaft, with respect to a scaffold on the side of a building.

Accordingly, it is an object and advantage of this invention to provide a factor of safety for a workman or an operator on a scaffold suspended from the roof or upper part of a building; a further object is to provide 2 a relatively simple device and method for increasing the safety of the workman or operator on a scaffold; an additional object is to provide asafety device having few moving parts; an additional object is to provide a safety device having no shafts, no bearings, no hinges to freeze and become inoperative; another object is to chanical-electric safety device for a rotating shaft and,

especially, a scaffold; an additional object is to provide a control for a too rapidly rotating shaft; an additional object is to provide a control for a shaft positioned at a precarious angle with respect to the horizontal; another object is to provide a control for controlling both the combination of a too rapidly rotating shaft and said shaft being-positioned at a precarious angle with respect to the horizontal; another object is to provide a control device for a winch; another object is to provide a safety device relatively free of maintenance; an additional object is to provide a safety device which can control the angular velocity of a rotating shaft in one direction but not in the opposite direction; a further obvice can, after being used, readily be reset by rotating IN THE DRAWINGS: I

' FIG. 1 is a fragmentary exploded perspective view looking at a winch-having a shaft, a cam on said shaft, a rotatable member of a brake having a cam and a stationary member of the brake;

FIG. 2, on an enlarged scale, illustrates the other face of the rotatable mamber of the brake and shows the channel defined by a first shoulder and a second shoulder and a moving means for moving into the entrance of said channel;

FIG. 3, on an enlarged scale, is a fragmentary view of the stationary member of the brake, a stop on said stationary member, the moving means onthe trailing edge of said stop and a first shoulder in contact with said moving means;

FIG. 4 illustrates the moving means on the leading edge of the stop and illustrates a first shoulder bearing against said moving means and which moving means prevents and stops the rotation of said shoulder and the rotation of said rotatable member of the brake;

FIGS. 5 through 12 illustrate the movement of the moving means in the channel with respect to the stop when there is a condition of overspeed of the shaft so that the moving means becomes positioned on the leading edge of the stop and not on the trailing edge of the stop;

FIG. 5 illustrates the moving means on the trailing FIG. 7 illustrates the moving 'means entering the entrance to the channel between the first shoulder and the second shoulder and moving in a counterclockwise direction;

FIG. 8 illustrates the moving means in the channel and moving in a counterclockwise direction with the counterclockwise movement of the first shoulder and the second shoulder;

FIG. 9 illustrates the moving means moving in a counterclockwise.direction but not having sufficient speed with respect to the rotational speed of the rotatable member of the brake to escape from the exit of said channel;

FIG. 10 illustrates the moving means moving in a clockwise direction in said channel while said rotatable member and said shoulders move in a counterclockwise direction;

FIG. 11 illustrates the moving means escaping from the entrance of said channel while said. rotatable mem-- ber moves in a counterclockwise direction so that said moving means enters a direction for movement against the stop;

FIG. 12 illustrates the moving means on the leading edge of said stop and said first shoulder bearing in a counterclockwise direction against said moving means so as to force the moving means against the stop and, also, so that the shoulder ceases to rotate and the rotatable member of the brake ceases to rotate;

FIG. 13 illustrates the relative position of the cam on the shaft and the cam on the rotatable member before the shoulder on the rotatable member contacts the moving means which is on the leading edge of the stop or, to state otherwise, the position of said cams at some time intermediate of the position of the moving means with respect to the stop as depicted in FIGS. 1 l and 12;

FIG. 14 illustrates the rotatable movement of the shaft and the cam on the shaft with respect to FIG. 13, so as to longitudinally force the cam on the rotatable member of the brake and said rotabable member of the brake against the stationary member of the brake so as to stop the rotation of the shaft on the winch and also the cam on said shaft;

FIGS. 15 through 24 illustrate the operation of this invention for activating a brake when the-scaffold tilts and the winches on the scaffold tilt so as to be at a peecarious angle with respect to the horizontal;-

FIG. 15 is a schematic illustration of a scaffold which is substantially horizontal and which scaffold has two winches and which winches incorporate thisinvention;

FIG. 16, on an enlarged scale, is a lateral crosssectional view of the rotatable member of the brake and illustrates the first shoulder and the second shoulder defining a channel for the moving means and the moving means in said channel when the winch is substantially horizontal;

FIG. 17 illustrates the scaffold when the scaffold has tilted so that one end of the scaffold is lower than.the other end and the scaffold is at a precarious angle with respect to the horizontal;

FIG. 18 is a lateral cross-sectional view illustrating the rotatable member of the brake, the first shoulder and the second shoulder defining the channel and the moving means about to enter the entrance of said channel when the scaffold and winches are in the position illustrated in FIG. 17 and the rotatable member of the brake is rotating in a counterclockwise direction;

FIG. 19 is a fragmentary view of the invention and illustrates the winch and the invention. in the substantially horizontal position and illustrates the large potential energy of the moving means in the entrance of the channel with respect to the exit of the channel so that the moving means will leave the exit of the channel and be on the trailing edge of the stop at a slow rotational speed of the shaft and the rotatable member of the brake;

FIG. 20 is a lateral cross-sectional view illustrating the moving means in the channel of FIG. 19 and also illustrates the potential-energy of said moving means in the entrance of said channel with respect to the exit of said channel so that said moving means escapes from the channel to be on the trailing edge of the stop;

FIG. 21 illustrates the shaft and the invention at an angle and also illustrates the low potential energy of the moving means between the entrance and the exit of the channel and which low potential energy means that the moving means will not be able to escape from the exit of the channel and be on the trailing edge of the stop but will escape from the entrance to the channel and be on the leading edge of the stop;

FIG. 22 is a more extreme view of the precarious angle of the winch with respect to the horizontal and shows the winch approaching avertical angle and also illustrates the low potential energy of the moving means between the entrance and the exit of the channel and which low potential energy means that said moving means will not'be able to escape from the exit of the channel and be on the trailing edge of the stop but will escape from the entrance of the channel and be on the leading edge of the stop;

FIG. 23 illustrates the winch and the invention tilted at another angle with respect to the horizontal, as contrasted with the angle and tilt illustrated in FIGS. 21 and 22, and shows the relatively small potential energy of the moving means between the entrance'and the exit of the channel and which moving means will not have sufficient energy to escape from the exit of said channel and be on the trailing edge of the stop but will escape from the entrance to said channel and be on the leading edge of the stop;

FIG. 24 is another illustration of the winch and the invention at another angle, as contrasted with the angles of FIGS; 21 and 22, and which shaft is at a precarious angle with respect to the horizontal and also illustrates the low potential energy of the moving means between the entrance and the exit of the channel and which moving means will not have sufficient energy to escape from the exit of the channel so as to be on the trailing edge of the stop but will escape from the entrance to the channel so as to be on the leading edge of the stop;

FIG. 25 is a fragmentary illustration of the winch and the shaft in the invention and with the rotatable member having a peripheral shoulder and braking material on the shoulder so as to contact the stationary member of the brake;

FIG. 26, taken on line 2626 of FIG. 25, is a lateral cross-sectional view illustrating the rotatable member, the first shoulder, the second shoulder and the channel defined by said shoulders and the moving means in said channel;

FIG. 27 is a fragmentary view of the invention and illustrates in place of a fixed stop on the stationary member of the brake, a movable stop which can be connected to an electrical circuit for activating an indicator;

FIG. 28 is a fragmentary end view of FIG. 27 and illustrates said movable stop; Y

FIG. 29 is a fragmentary lateral cross-sectional view illustrating said movable stop and the moving means bearing against said movable stop;

FIG. 30 is another modification of the invention and illustrates the moving means in the channel and also illustrates a rotatable stop;

FIG. 31, taken on line 3131 of FIG. 30, illustrates the rotatable stop and which rotatable stop is in an electrical circuit for activating a switch and which switch is in an open state;

FIG. 32 illustrates the rotatable stop as being rotated soas to close the switch;

FIG. 33 is a fragmentary exploded perspective view illustrating the winch, a shaft, a camonthe shaft, a rotatable member of the brake and a cam on said rotatable member, the stationary member of the brake, see FIG. 1, and also the electrical alarm unit of FIGS.

FIG. 34 is a schematic illustration of a carriage on a track, and which track and carriage may be on the roof of a building, and illustrates the two winches on said carriage and, the subject invention on a secondary shaft driven by sprockets from the common shaft for the two winches for controlling the electrical motor for driving the bull gear and the common shaft, and also illustrates another unit, see FIGS. 27-29 on the secondary shaft,

for activating the self-energizing brake for the winches;

FIG. 35 is an end elevational view of the carriage on the track, the winch, the brake band on the winch, and a scaffold or platform suspended by the cables from an overhanging beam on the carriage;

FIG. 36, taken on line 36-36 of FIG. 34, illustrates the sprocket on the common shaft,'the sprocket on the secondary shaft and the chain interconnecting said sprockets;

FIG. 37 is a perspective exploded view illustrating the stationary member of the brake and a removable stop for testing said brake; and,

FIG. 38 is a view of the rotatable member of the brake and illustrates the moving means encountering said removable stop so that said moving means cannot escape from the exit of the channel and fall on the trailing edge of the stationary stop of the stationary member but must fall so as to be on the leading edge of the stationary stop of the stationary member.

With reference to FIGS. 1, 2, 3, 4, and 13, it is seen that the invention 50 may be used in conjunction with a winch.

The winch comprises a shaft 52.'There is positioned on the shaft 52 a drum body 54, a first flange 56 and a second flange 58. The first flange 56 and the second flange 58 are spaced apart. There is a circular shoulder 60 on the second flange 58 and which circular shoulder 60 is directed away from the first flange 56.

On the shaft 52 there is a cam 62 having a cam face The invention 50 comprises a rotatable member 66 of a brake. The rotatable member 66 has a passageway or a hole 68 in the central portion. On that face of the rotatable member 66 facing the second flange 58 there is a cam 70 having a cam face 72. The cam 70 is juxtapositioned with respect to the passage-way 68.

In FIG. 2 it is seen that the rotatable member 66 hasa circumferential brake surface 74 on that l'ace away from the second flange 58,.

The rotatabl member 66 has a central hub 76 juxtapositioned to the passageway 68. There surrounds the hub 76 a first shoulder 78 which is elongated toward the circumferential brake surface 74 so as to form a dog 80. It is seen in FIG. 2 that in the dog 80 there is a passageway 82.

There surrounds approximately over one-half of the first shoulder 78 a second shoulder 84. The second shoulder 84 near one end, and on that surface facing the first shoulder 78, has a flat portion 86. The first shoulder 78 and the second shoulder 84 define a channel 88.

There is a moving means 90 which may move in and out of the channel 88.

For reference there may be considered to be an entrance 92 to the channel 88, see FIG. 2 wherein the moving means 90 is movinginto said entrance 92; and, on exit 94 from the channel 88.

There is a stationary member96'of thebrake and which stationary member 96 has a circular shoulder 98. The circular shoulder 98 may be considered to be a brake surface of a disc brake. In the stationary member 96 there is a-passageway 100. Y

The stationary member of the brake 96 comprises a housing 102 fora bearing. The stationary member 96 I is positioned on a stationary base 104.

Inside the circular shoulder 98 and projecting from the main body of the'stationary member 96 there is a stop 106. In FIG. 1 it is seen that this stop 106 is positioned in the lower part of the stationary'member of the brake 96 or at'the lowest elevation of the stationary member 96. I

There is a spring 108 positioned between the station ary member96 and the rotatable member 66 so as to urge the rotatable member 66 away from the stationary member 96.

In FIG. 13 there is illustrated the cam 62 on the shaft 52 and with the cam62 in contact with the cam of the rotatable member 66 so as to drive or rotate the rotatable member 66 with the rotation of the shaft 52.

In FIG. 3 there is illustrated the moving means 90 or sphere 90 on the trailing edge 1 10 of the stop 106. Further, the shaft 52 is rotating in a clockwise direction and the dog is bearing against the moving means 90. The dog 80 is of a flexible material. The dog 80 may be a flexible material such as a suitable plastic-like a polyurethane, a rubber such as a neoprene rubber, or another suitable plastic such as tetrafluoropolyethylene. Normally, the shaft 52 and the dog 80 will rotate in a counterclockwise direction. However, in FIG. 3 the shaft 52 and the dog 80 are rotating in a clockwise direction. The dog 80 may be considered to have a trailing edge 112 and a leading edge 114. When the dog 80 is rotating in the counterclockwise direction, the edge 1 14 is the leading edge and the edge 112 is the trailing edge. e

In FIG. 3 it is seen that the dog 80 is rotating in a clockwise direction and that the moving means is on the trailing edge of the stop 110. It would be assumed that the dog 80 would not be able to pass over the moving means 90. However, due to the flexible nature of the dog 80 and the passageway 82 near the leading edge 114, the dog 80 deforms so that the dog 80 may pass over the moving means 90 while rotating in a clockwise direction.

As contrasted with this in FIG. 4 with the shaft 52 and the dog 80 moving in a counterclockwise direction, and the moving means 90 being on the leading edge 116 of the stop 106, the dog 80 will not deform. Instead, the dog 80 will not pass over the moving means 90 but will be positioned with the leading edge 114 bearing against the moving means 90 and the moving means 90, in turn bearing against the stop 106. In this situaion, the dog 80 cannot rotate. When this occurs, the relative movement of the cam 62 and the shaft 52 and the cam 70 on the rotatable member 66 takes place, see FIG. 14. The cam 62 on the shaft 52 is in contact with the cam 70 on the rotatable member 66 so that the cam face 64 is pressing against the cam face 72. Remember, the rotatable member 66 is not free to rotate because the moving means 90 is on the leading edge 116 on the stop 160. This prevents the rotation of the rotatable member 66. However, with the rotation of the shaft 52 and the rotation of the cam 62, the cam 62 forces the cam 70 and the rotatable member 66 toward the stationary member 96 and the disc brake 98. Finally, the brake surface 74 and the rotatable member 66 are bearing against the disc brake 98 and no further longitudinal movement of the rotatable member 66 can take place on the shaft 52. Then, the shaft 52 can no longer rotate. As a result, the drum body 54 of the winch cannot rotate and the winch cannot rotate. This means that the winch cannot rotate and the cable 118 cannot unwind from the drum body 54 or the winch. An illustration of this is in FIG. 14.

In FIGS. 5 through 12 there is illustrated the rotation of the rotatable member 66 in a counterclockwise direction and the movement of the moving means 90 in the channel 88. In FIGS. 5 through 12 the rotatable member 66 is rotating at a too rapid angular velocity or at a not safe angular velocity. The moving means 90 can enter the normal entrance 92 for the channel 88 but cannot exit from the normal exit 94 of the channel 88 but exits from the entrance 92 so as tofall and assume a position of the leading edge 116 of the stop 106 with the result illustrated in FIG. 14 and the stopping of the rotation of the shaft 52.

In FIG. 5 there is illustrated the moving means 90 on the trailing edge of the stop 106. The rotatable member 66 is rotating in a counterclockwise direction and the leading edge 114 of the dog 80 is approaching the stop. 106.

In FIG. 6 the leading edge 114 of the dog 80 has contacted the moving means 90 and is moving the moving means 90 in a counterclockwise direction.

In FIG. 7 the moving means 90 and the dog 80 are moving in a counterclockwise direction and the moving means 90 is about to move into the entrance 92 and the channel 88.

In FIG. 8 the moving means 90 and the dog 80 are moving in a counterclockwise direction and the moving means 90 is in the channel 88.

In FIG. 9 the dog 80 is moving in a counterclockwise direction and the moving means 90 is, substantially, not

In FIG. 10 the rotatable member 66 and the dog are rotating in a counterclockwise direction while the moving means is moving in a clockwise direction and back into the channel 88.

In FIG. 11 the rotatable member 66 and the dog 80 are rotating in a counterclockwise direction while the moving means 90 is moving in, substantially, a clockwise direction and escaping from the channel 88 by means of the normal entrance 92. With the further rotation of the rotatable member 66 in a counterclockwise direction, the moving means 90 will roll so as to be in a position on the leading edge 116 of the stop 106.

In FIG. 12 it is seen that the moving means 90 is on the leading edge 116 of the stop 106 and the dog 80 is bearing against the moving means 90. The FIG. 12 is similar to the FIG. 4. With the moving means 90 on the leading edge 1160f the stop 106 and the dog 80 bearing against the moving means 90, the cam 62 bears against the cam 70 so as to force the rotatable member 66 against the stationary member 96 and, with the result, that the rotatable member 66 contacts the stationary member 96. The shaft 52 ceases to rotate as previously explained.

In FIG. 15 there is illustrated a scaffold having two spaced apart winches 122 with a cable or rope 118 sttached to each winch 122. Each winch 122 comprises the subject invention 50.

In FIG. 15 it is seen that the scaffold 120 is substantially horizontal.

In FIG. 16 it is seen that the moving means 90 is in the channel 88, defined by the first shoulder 78 and the second shoulder 84. Also, in FIG. 16 it is seen that the rotatable member 66 is substantially vertical.

If the scaffold 120 descends at a safe velocity or speed, thenthe moving means 90 will enter the channel 88 by means of the entrance 92 and exit from the channel 88 by means of the exit 94. However, if the scaffold 120 descends at a too great velocity or too high speed, then the moving means 90 will enter the channel 88 by means of the entrance 92 and will, abnormally, exit from the entrance 92 so as to assume a position on the leading edge 1 16 of the stop 106. As a result, the rotatable member 66 will contact the stationary member 96 and the winch 122 will cease to function and the wire rope or cable 118 will not move. In other words, the safety feature is in operation and the scaffold 120 cannot, further, descend because of the roo rapid descent of the scaffo'd 120.

FIGS. 17 through 44 should be considered together. These figures illustrate the effect of the tilt of the invention 50 or, to phrase it differently, the effect of the deviation of the invention 50 from a horizontal position to an anglewith the horizontal.

In FIG. 17 there is illustrated the scaffold 120 with the scaffold tilting or at an angle with the horizontal.

In FIG. 18 the invention 50 is at an angle and the moving means 90 is about to enter the entrance 92 of the channel 88. With a sufficiently large angle of the invention 50 to the horizontal or a sufficiently great tilt, the moving means 90 will not be able to exit from the exit 94 or the channel 88 but will exit from the channel 88 by means of the entrance 92 and thereby assume a position on the leading edge 116 of the stop 106. The result of the moving means 90 on the leading edge 116 of the stop 106 has previously been explained.

In FIGS. 19 through 24 there is illustrated the difference in potential energy between the moving means 90 entering the entrance 92 of the channel 88 and exiting through the exit 94 of the channel 88 when the invention 50 is substantially horizontal, as compared when the invention 50 is at a considerable angle with the horizontal. More particularly, there is illustrated the vertical distance the moving means 90 will move in the channel 88 for various angles of the invention 50 with respect to the horizontal. Naturally, with the greatest potential energy for the moving means 90 there is the greatest possibility of the moving means 90 exiting from the exit 94 for the channel 88 and assmming a position on the trailing edge 110 of the stop 106. This allows the shaft 52 to continue to rotate.

In FIGS. 19 and 20 the invention 50 is in a substantially horizontal position, similar to FIGS. and 16, with the moving means 90 in the entrance 92 of the channel 88.

In FIGS. 19 and 20 the line 130 represents the position of the moving means 90 in the entrance 92 and the line 132 represents the position of the moving means 90 in theexit 94 of the channel 88. The arrows 134 between the lines 130 and l32-illustrate the potential en-- ergy between the entrance 92 and the exit 94 when the invention 50 is in a substantially horizontal position or the shaft 52 is in a substantially horizontal position and the rotatable member 66 is in a substantially vertical position. In this position there will be sufficient energy, if the shaft 52 is not rotating too rapidly, for the moving means 90 to exit from the exit 94 and to assume a posi tion on the trailing edge 1 10 of the stop 106. However,

if the shaft 52 is rotating too rapidly, then the moving V means 90 will exit in the channel 88 by means of the entrance 92 and assume a position on the leading edge 116 of the stop 106 with the result that the shaft 52 will cease to rotate when the rotatable member 66' presses against the stationary member 96.

In FIG. 21 the position of the invention is deviating from the horizontal position or tilting so that the longitudinal axis of the-shaft 52 is assuming an angle with respect to the horizontal and the rotatable member 66 is assuming an angle with respect to the vertical. 1

In this position the arrow 136 denotes the vertical'dis tance between the entrance 92, line 130, to the channel 88 and the exit 94, line 132, from the-channel 88. The length of the arrow 136 is less than the length of the arrow 134, see FIG. 19. With this less length of the arrow 136 or less vertical distance between the entrance 92 and the exit 94 there is less potential energy for the moving means 90 to move out of the exit 94. There is the possibility that the moving means 90 will not move out of the exit 94 but will move out of the entrance 92 and assume a position on the leading edge 116 of the stop 106. Also, there is the possibility that the combination of the angle of the invention 50 and the rotational speed of theshaft 52 will be such that the moving means 90 will not move out of the exit 94 but will move out of the entrance 92. I

In FIG. 22 it is seen that the invention 50 is tilted a considerable degree and that the longitudinal axis of the shaft 52 has assumed a position more than 45 with speed of the shaft 52, exit from the channel 88 by 10 means of the exit 94, the moving means will exit from the channel 88 by means of the entrance 92, assume a position on the leading edge 116 of the stop 106, with the result that the shaft 52 will cease-to rotate.

140 indicates the vertical distance between the entrance 92, line 130, and the exit 94, line 132. It is seen in FIG. 23 that the longitudinal axis of the shaft 52 is at an angle with respect to the horizontal and that the rotatable member 66 is at an angle with respect to the vertical. Thelength of the arrow 140 is less than the length of the arrow 134, see FIG. 19. The vertical distance 140 is such that if the shaft 52 rotates at a slot speed, the moving means 90 will exit fromthe channel 88 by means of the exit 94 and assume a'position on the trailing edge of the stop 106. However, if the shaft 52 is rotating at a relatively fast rotational speed, the moving means 90 will not exit from the channel 88-by means of the exit 94 but will exit from the channel 88 by means of the entrance 92 and assume a position on the leading edge 116 of the stop 106. The combination of the rotational speed of the shaft 52 and the vertical distance between the entrance 92 and'the exit 94 will determine if the shaft 52 continues to rotate or ceases to rotate. 1

In FIG. 24 the invention 50 is tilted in the opposite direction from that illustrated in FIGS. 21- and 22. The I length of the arrow 142, the distance between the entrance 92, line 130, and the exit 94, line 132, is relatively short. The longitudinal axis of the shaft 52 has speed there is, probably, not sufficient energy for the moving means 90 to exit from the channel 88 by means of the exit 94. Probably, the moving means 90 will exit 152 having a first shoulder 154 and a second shoulder I56. Theishoulders 154 and 156 define a passageway or channel 158.

The rotatable member 152 has a circular shoulder 160. Also, the rotatable member 152 has a cam 162 which faces the cam 62. The first shoulder 154, the second should 156 and the circular shoulder 160 are on that side of the rotatable member 152 away from the cam 162. On the outer surface of the circular shoulder 160 there is a brake surface 164.

In the rotatable member 152 there is a passageway The modification comprises a stationary member 168 having a housing 170. The housing 170 is the housing for the bearing for theshaft 52. The stationary member comprises a circular plate 172. In the circular member 168 there is a passageway 174 for receiv- In FIG. 23 the moving means 50 is tilting inthe oppo site direction to the tilt of FIGS. 21 and 22. The arrow ing the shaft 52. The stationary member 168 is positioned on a stationary base 176.

In the lower part of the plate 172 there is a peg 178 which extends through the plate 172 and is directed toward the rotatable member 152. The peg 178 actually comprises the stop and corresponds to the stop 106 of the invention 50.

The shoulder 154 also comprises a dog 180, corresponding to the dog 80 of the invention 50. In the dog 180 there is the passageway 182. The dog 180 may be of the same materials as-the dog 80 and may function the same as the dog 80. In other words, the dog 180 may yield when necessary as the dog 80 yields and may be firm, as necessary as the dog 80 is firm.

In operation, when the moving means 90 is on the leading edge of the stop 178 the leading edge of the dog 180 will contact the moving means 90. The leading edge of the dog 180 will force the moving means 90 against the stop 178 and will not pass over the moving means90 and the stop 178. As a result, the rotatable member 152 ceases to rotate. However, the shaft 52 is continuing to rotate. As a result the cam face 64 of the cam 62 rotates so as to contact the cam face 190 of the cam 162. In time, the cam 62 forces the cam 162 and the rotatable member 152 into contact with the stationary member 168 so that the brake surface 164 of the rotatable member 152 contacts the surface of the stationary plate 162. The result is that the rotatable member 152 and the shaft 52 cease to rotate because the rotatable member 152 is bearing against the stationary member 168 and cannot move and cannot rotate. In effeet, the shaft 52 has ceased to rotate and the winch on the shaft 52 cannot rotate and the cable or rope 118 on the winch cannot unwind.

In FIG. 27 there is illustrated a modification 200 of the invention. There is the shaft 52. Mounted on the shaft 52 is a rotatable member 202 comprising a first shoulder 204, a second shoulder 206 and a circular shoulder 208. The first shoulder 204 and the second shoulder 206 define a first channel 210. There is a moving means 90 which may move in and out of the channel 210.

In the rotatable member 202 there is a passageway 205 for shaft 52. There is a stationary member 212 having a housing 214. In the said housing 214 there is a passageway 216 which functions as a bearing for the shaft 52. The stationary member 212 provides a circular disc or circular plate 218. The shoulders 204, 206 are directed toward the circular plate 218.

The first shoulder 204 comprises a dog 220 which corresponds to the dog 180. The dog 220 may be of the same materials as the dog 180. In the dog 220 there is a first passageway 222. On the outside surface and the lower part of the circular plate 218 there is a housing 224. In the housing 224 in the circular plate 218 there is a passageway 226.

There is positioned in the passageway 226 a deflector plate 228. The deflector plate 228, to a degree, corresponds to the stop 106 or to the stop 178. It is seen that the end of the deflector plate 228 is directed toward the rotatable member 202. The end of the deflector plate 228 is at an angle 230, or presents a diagonal face 230.

There is attached to the lower part of the housing 224 a first hook 232. There is attached to the outer part of In FIG. 29 it is seen that the outer end of the deflector plate 228 is enlarged at 238 so as to prevent the movement of the deflector plate 228 toward the rotab able member 202 so that the deflector plate 228 does not contact the rotatable member 202.

In operation, if the moving means 90 does not exit from the exit 94 between the shoulders 204 and 206 or the channel 210 so as to be on the trailing edge of the deflector plate 228, then the moving means 90 will exit from the entrance 92 of the channel 210 so as to be on the leading edge of the deflector plate 228. With further rotation of the rotatable member 202, the leading edge of the dog 220 will contact the moving means 90.

the plate 228 a hook 234. A spring 236 runs between t the two hooks 232 and 234 so as to urge the deflector plate 228 toward the rotatable member 202.

Then, the dog 220 and the moving means 90 will force the deflector plate 228, see FIG. 29, to the right and will force the diagonal face 230 to the right or away from the rotatable member 202. The dog 220 moves the moving means 90 past the deflector plate 228 as the deflector plate 228 moves to the right and out of the path of the moving means-90.

There is illustrated in FIG. 30 a variation of the overspeed and positioning device. This variation is identified by reference numeral 250. It comprises an integral housing having a first member 252 and a second member 254. I

Wherever possible the same reference numeral will be used with respect to FIGS. 30, 31, and 32 as used with respect to FIGS. 1 and 2.

The first member 252 comprises a circular plate 256. The circular plate 256 has a peripheral circumscribing flange 258. Also, the first member 252 comprises the second shoulder 84 with the flat surface 86, a first shoulder 78, a dog and a passageway 82. The first member 252 has a hub 260 with a passageway 262 therethrough. Also, the hub has a keyway 264. There is the shaft 52. The shaft 52 has a keyway 266. The first member 252 is mounted on the shaft 52 by means of a key 268.

The second member 254 comprises the circular plate 270 having a peripheral circumscribing flange 272. The second member 254 has a through passageway 274'.

The outer end of the shaft 52 is threaded at 276.

The second member 254 is positioned on the shaft 52 with the flange 272 directed inwardly and toward the flange 258. Then, a nut 280 may be screwed onto the threaded end 276 so as to definitely position the second member 254 in the shaft shaft 52.

In FIG. 30 it is seen that the length of the flange 258 'is not as long as the lengthof the second shoulder 84 and the first shoulder 78. Also, the length of the flange 272 is not as long as the second shoulder 84 and the first shoulder 78. The two flanges 258 and 272 do not meet and therefore define an opening 282 between the two members 252 and 254.

There is a rotatable shaft 284. On the rotatable shaft 284 there is positioned an animated stop 286. The animated stop 286 has a body portion 288. On the upper left end there is a recess 290 having a sloping inset side 292. The side 292 with the upper surface 294 defines a catch 296.

On the lower left part of the animated stop 286 there is a curved portion or a cam 298.

The overspeed and positioning device 250 has the channel 88 defined by the second shoulder 84 and the first shoulder 78. Also, it has the moving means 90. There is an inlet 92 to the channel 88 and an exit 94 to the channel 88.

If the overspeed device'250 rotates at a slow speed, the moving means 90 will 'enter the entrance 92 of the channel 88 and exit from the exit 94 of the channel 88 so as to fall on the trailing edge of the animated stop 286, viz.,- on that edge having the flat surface 300. However, if the device 250 rotates too rapidly, or is at too great an angle with the horizontal, or a combination of too rapid a rotation and too great an angle at the hor izontal, the moving means 90 will enter the channel 88 by means of the entrance 92 but will also exit from the channel 88 by means of the entrance 92 so as to be on the leading edge of the rotatable stop 286, viz., next to the catch 296. In that instance, see FIG. 32, the rotatable stop 286 will rotate. However, in this instance the rotatable stop 286 will not stop in rotation of the device 250 but the dog 280 will push the moving means 90 past the catch 2960f the animated stop 286 so as to force the animated stop 286 to assume the position 302, see the dotted line in FIG. 32 of the animated stop 286. In other words, the dog 80 will push the moving means 90 past the catch 296 of the animated stop 286 so as to keep pushing around the moving means 90. The animated stop 286 is rotated out of position so that the catch 296 does not stop the'movement of the dog 80 and the moving means 90.

From FIGS. 31 and 32, it is seen that there is a first electrical contact 306 and'a second electrical contact 308. An electrical wire 310 connects with the first contact 306, and an electrical wire 312 connects with the second contact 308. As illustrated in FIG. 31, the contacts 306 and 308 are in a normally open position. With the rotation of the member 250 and the moving means 90 on the leading edge of the animated stop 286, the animated stop 286 is rotated so as to force the second contact 308 to move to be in contact with the first contact 306 so as to close the circuit. As can be readily appreciated, the contacts 306 and 308 upon closing the circuits can actuate a relay to sound an alarm, to open the circuit leading to the motor for operating the winch and for rotating the shaft 52. Then, with the opening of the electrical circuit to the motor for rotating the shaft 52, the shaft 52 ceases to rotate and the winch on the shaft 52 ceases to rotate.

The animated stop 286 is connected by means of a spring 312 to a fixed body 314 or to a permanentinstallation such as a building, scaffold, or supporting structure 314. I

To preclude the animated stop 286 from rotating too far in a counterclockwise direction there is provided a fixed stop 316. In FIG. 31 it is seen that the animated stop 286 is bearing against the fixed stop 316.

In FIG. 33 there is illustrated the combination of the invention and the invention 252. More particularly, thereis the shaft 52, the first flange 56, the drum body 54, the second flange'58 and the circular shoulder 60,

the cable or rope 118 on the drum body 54, the cam 62 may be a sealed housing to preclude extraneous matter contacting the positioning device 250.

The combination of FIG. 33 makes it possible to stop the rotation of the shaft 52 by means of the dog pressing the moving means 90 on the leading edge 116 of the stop 106. Further, it is possible to interrupt the electrical circuit to the motor for driving the shaft 52 by means of the device 250, as previously explained with respect to FIGS. 30, 31, and 32.

In FIGS.'34, 35, and 36 there is illustrated a modification of the invention. On the'roof 328 of the building there are two spaced apart rails 330.

There is a carriage 332 comprising a base 334. The base 334 has attached on its underneath side trunions 336. There is mounted on the trunions 336 wheels 338. Naturally, the wheels 338 ride on the rails 330.

The carriage 332 has upright supports 340. The upright supports support a crossarm 342. Above the base for the carriage and carried by the crossarm 342 is a pulley or sheave 344. On the outer end of the crossarm 342 is a pulley or sheave 346.

On the upper part of the base 334 are threespaced apart upright pedestals 350.

The upright pedestals 350 support a common shaft 352. There is mounted on the common shaft 352 a first drum 354 and a second drum 356.

- Also, there is mounted on the common shaft 353 a bull gear 358. 1

There is mounted on the upper surface of the base 334 a motor 360. The motor 360-has an output shaft 362. There is mounted on the output shaft 362 a pinion gear 364. The pinion gear 364 is in a driving relationship with the bull gear 358.

There is mounted on the common shaft 352 a sprocket 366.

There is mounted on the upper surface of the base 334 a pedestal 368 and a pedestal 370. A shaft 37 2 is supported by the pedestal 368. On the pedestal 370 there is a bearing 102. The shaft 372 is journaled in the bearing 102.

There is mounted on the shaft 372 a sprocket 374. A chain 376 connects the sprocket 366 andthe sprocket 374.

On one end of the shaft 372 there is mounted a modification 250 of the invention. The modification v250 of the invention has been described with reference to. FIGS. 30, 31, and 32. There are two lead wires 376 and 378. The modification 250 has the normally open switch in a control box 380. When the switch is open, the circuit to the motor 360 is completed through the lead wires 376 and'378. However, when the circuit is closed between the leads 310 and 312 of the modification 250, the circuit to the motor 360 is open and the and the cam face 64. Also, there is the rotatable mem- 1 her 66 of the brake, the cam 70 and the cam face 72,

' the spring 108, the circular shoulder brake surface disk motor is not energized. 1

On the other end of shaft 372 there is illustrated the modification 200 of the invention. The modification 200 of the invention is more particularly described with reference to FIGS. 27, 28, and 29. The modification 200 has the movable deflector plate 228.

The drum 356 has a brake surface 384 a brake band 386. On one end of the brake band 386 there is a connection with a weight 388. The weight 388 is supported by a movable support 390 positioned under the weight 388. If the deflector plate 228 moves to the right, the deflector plate 228 will move the support 390. Then, the weight 388 will descend so as to tighten the brake band 386 on the brake surface 384.

There is a platform 394. The platform 394 is suspended by two cables, 396 on the drum 354 and 398 on the drum 356. If the platform 394 descends too rapidly, the modification 250 of the invention will be activated so the animated stop 288 rotates to close the contact 310 and 312. With the closing of the contacts 310 and 312, the control box 380 is so activated as to open the circuit leading to the'electric motor 360. Then, the

electric motor 360 is not energized and, theoretically,

the shaft 362 and the pinion gear 364 will not rotate. Likewise, the bull gear 358 and the common shaft 352 will not rotate. However, if by some chance the common shaft 362 continues to rotate, the modification 200 will be activated so that the deflector plate 228 will move to the right, see FIG. 32, and move the support 390 from underneath the weight 388. Then, the weight 388 will descend so as to tighten the brake band 386 on the brake surface 384 of the drum 356. This tightening of the brake band 386 on the brake surface 384 should definitely stop the movement of the brake drum 356 and, likewise, the movement of the common shaft 352. Therefore, there is a positive braking action by the brake band 386 on the brake surface 384.

In many buildings instead of having a platform suspended by one or more cables and the motor and winch mounted on the platform there is a carriage on top of the building such as carriage 332, having the motor and winches on the carriage. The platform does not carry motors and winches. The platform is suspended by the carriage by means of the pulleys 346 and 344 on the crossarm. It is seen that the crossarm 342 extends far enough away from the carriage 332, and over the edge of the building, so that the platform 394 can be lowered for the window washers and maintenance men to work on the building. In FIG. 35 it is seen that the platform is suspended by the cables 396 and 398 which run around pulleys 346 and 344 and back to the drums or winches. This is one modification of apparatus for window washing and maintenance of the exterior of a building. The other modifications show a platform with winches and motors mounted on the platform.

From the foregoing it is seen that the applicants invention can be used on a platform having motors and winches mounted on the platform or can be used in combination with a carriage having motors and winches mounted on the carriage and the platform suspended. In both instances the applicants inventions have provided a degree of safety for the person working on the platform.

FIGS. 37 and 38 illustrate a modification of the invention 50 for testing for a simulated overspeed condition. Normally, there would not be an overspeed condition unless there was some mistake in the invention 50. It would be possible to rotate the shaft 52 at a known, not safe speed, to test the invention 50. However, it is possible, with the modification illustrated in FIGS. 37 and 38, to rotate the shaft 52 at a slow speed and yet simulate an overspeed state for the shaft 52.

This is accomplished by drilling a passageway 410 in the main body of the stationary member 96. This passageway is drilled so as to terminate near the periphery of the rotatable members 66. Then, a tool 412 having a handle 414 and a shaft or pin 416 may be inserted in the passageway 410 so that the end of the shaft 416 points toward the face of the rotatable member 66 and ends near the face of the rotatable member 66.

does not rotate. However, the member 66 rotates.

When the member 66 is in the position illustrated in FIG. 38 and the tool 412 is in the passageway 410, the tool 412 will not allow the moving means 90 to escape from the exit 94 of the passageway 88. Remember, normally, when the moving means 90 cannot escape from the passageway 88, the shaft 52 is either rotating at too rapid an angular velocity or the shaft 52 is at too great an angle with the horizontal or a combination of too rapid an angular.velocity and too great an angle with the horizontal. Under these conditions the moving means 90 will not escape from the passageway 88 by means of the exit 90 before but will escape from the passageway 88 by means of the entrance 92. Then,'the I moving means 90 is on the leading edge of 116 of the stop 106, see FIG. 4, and the dog cannot move past the moving means 90. This means that the rotatable member 66 is forced against the stationary member 96 with the result that the shaft 52 ceases to rotate.

From this it is seen that the tool 412 in the passageway 410 can be used to simulate a too rapid angular rotation of the shaft 52 or a too great an angle of the shaft 52 with the horizontal or a combination of a too rapid angular rotation and too great an angle with the horid. on that part of the first member facing said second member there being a stop;

e. on that part of the second member facing said first member there being a first shoulder and a second shoulder;

f. a moving means;

g. said first shoulder and said second shoulder defining a first channel for said moving means;

h. said first shoulder and said second shoulder defining a first entrancev and a second entrance for said first channel;

i. said first shoulder extending around part of said second shoulder;

j. a dog on said second member; 7

k. a third shoulder positioned on one ofsaid members and facing the other one of said members and spaced apart from said first shoulder; and,

I. said first shoulder and said third shoulder defining a second channel.

2. An apparatus according to claim 1 and comprising:

a. said second rotating member upon rotating at a slow speed in a first direction with said moving means on the trailing side of said stop said dog engages said said moving means and moves said moving means so as to enter said first channel through said first entrance; and,

b. said moving means moves through said first channel and exits through said second entrance to move through said second channel to be on said trailing edge of said stop.

3. An apparatus according to claim 1 and comprising:

a. said second rotating member-upon rotating at a fast speed in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and,

b. said moving means moves through a portion of said first channel and exits through said first entrance to be on the leading edge of said stop so that upon the rotation of said second rotating member then said dog bears against said moving means which is on the leading edge of said stop so as to stop the rotation of said second rotating member.

4. An apparatus according to claim 1 and comprising:

a. said third shoulder being on said first member,

5. an apparatus according to claim 1 and comprising:

11. An apparatus according to claim 1 andjcompris- I,

" ing:

a. said third shoulder being on said second member.

6. An apparatus according to claim 1 and comprising:

a. a shaft;

b. a first cam on said shaft; and, i

c. said second rotating member having on a second face facing said first cam a second cam.

7. An apparatus according to claim 3 and comprising:

a. a shaft; I

b. a first cam on said shaft; v

c. said second rotating member having on a second face facing said first cam a second cam; and,

d. when the rotation of said second rotating member stops and said shaft continues to rotate, said first cam bears against said second cam to force said second member toward said first member.

8. An apparatus according to claim 1 and comprising:

a. said second rotating member upon rotating in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through saidfirst entrance; and, b. with said first entrance being at a sufficient height above said second entrance,'said moving means in moving through said first channel acquires sufficient velocity to exit through said second entrance.

cient velocity to exit through said second entrance and with the continued rotation of said second member for said moving means to exit through said first entrance to be on theleading edge of said stop so that upon the rotation of said second rotating member, then said dog bears against said moving means which is on the leading edgeof said stop so as to stop the rotation of said second rotating member. 10, An apparatus according to claim 9 and comprisa. said second rotating member upon being positioned at an angle other than thevertical, then said first entrance being at said low height above said second entrance.

a. said second rotating member upon rotating in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving'means so as to enterb. with said moving means on said trailing edge :of I said stop and with said second rotating member rotating in said first direction, then said leading surface contacts said moving means to move said moving means away from said stop;

c. with said moving means on said trailing edge of said stop and with said second rotating member rotating in a second direction, as opposed to said first direction, then said trailing surface contacts said moving means to force said moving means against said stop;

d. with said moving means on said leading edge of said stop and with said second rotating member rotating in said first direction, then said leading sur-v face contacts said moving means to force said moving means against said stop; and, s. with said moving means on said leading edge of said stop and with said second rotating member rotating in said second direction, then said trailing surface contacts said moving means to move said 7 moving means away from said stop. 13. An apparatus according to claim 12 and comprising: I

a. said dog being flexible. 14. An apparatus according to claim 12 and comprisa. said dog being flexible.

b. said dog being more flexible in the vicinity of said leading surface than in the vicinity of said trailing surface; 1

c. with said moving means on said trailing edge of said stop and with said second rotating member rotating in a second direction, then said trailing surface contacts said moving means to force said moving means against said stop and said dog deforms to pass over the combination of said moving means and said stop and to leave said moving means on said trailingedge of said stop; and,

d. with said moving means on said leading edge of said stop and with said secondv rotating member rotating in a first direction, then said leading surface contacts said moving means to force said moving means against said stop to stop the rotation of said second rotating member with respect to said first member.

15. An apparatus according to claim 1 and comprising: v l

a. said dog and said second shoulder being-integral. 

1. An apparatus, said apparatus comprising: a. a first member; b. a second rotating member; c. said first member and said second member juxtapositioned to each other; d. on that part of the first member facing said second member there being a stop; e. on that part of the second member facing said first member there being a first shoulder and a second shoulder; f. a moving means; g. said first shoulder and said second shoulder defining a first channel for said moving means; h. said first shoulder and said second shoulder defining a first entrance and a second entrance for said first channel; i. said first shoulder extending around part of said second shoulder; j. a dog on said second member; k. a third shoulder positioned on one of said members and facing the other one of said members and spaced apart from said first shoulder; and, l. said first shoulder and said third shoulder defining a second channel.
 2. An apparatus according to claim 1 and comprising: a. said second rotating member upon rotating at a slow speed in a first direction with said moving means on the trailing side of said stop said dog engages said said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. saiD moving means moves through said first channel and exits through said second entrance to move through said second channel to be on said trailing edge of said stop.
 3. An apparatus according to claim 1 and comprising: a. said second rotating member upon rotating at a fast speed in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through a portion of said first channel and exits through said first entrance to be on the leading edge of said stop so that upon the rotation of said second rotating member then said dog bears against said moving means which is on the leading edge of said stop so as to stop the rotation of said second rotating member.
 4. An apparatus according to claim 1 and comprising: a. said third shoulder being on said first member.
 5. an apparatus according to claim 1 and comprising: a. said third shoulder being on said second member.
 6. An apparatus according to claim 1 and comprising: a. a shaft; b. a first cam on said shaft; and, c. said second rotating member having on a second face facing said first cam a second cam.
 7. An apparatus according to claim 3 and comprising: a. a shaft; b. a first cam on said shaft; c. said second rotating member having on a second face facing said first cam a second cam; and, d. when the rotation of said second rotating member stops and said shaft continues to rotate, said first cam bears against said second cam to force said second member toward said first member.
 8. An apparatus according to claim 1 and comprising: a. said second rotating member upon rotating in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. with said first entrance being at a sufficient height above said second entrance, said moving means in moving through said first channel acquires sufficient velocity to exit through said second entrance.
 9. An apparatus according to claim 1 and comprising: a. said second rotating member upon rotating in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; b. with said first entrance being at a low height above said second entrance said moving means in moving through said first channel does not acquire sufficient velocity to exit through said second entrance and with the continued rotation of said second member for said moving means to exit through said first entrance to be on the leading edge of said stop so that upon the rotation of said second rotating member, then said dog bears against said moving means which is on the leading edge of said stop so as to stop the rotation of said second rotating member.
 10. An apparatus according to claim 9 and comprising: a. said second rotating member upon being positioned at an angle other than the vertical, then said first entrance being at said low height above said second entrance.
 11. An apparatus according to claim 1 and comprising: a. said second rotating member upon rotating in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. the exit of said moving means from the first entrance and the second entrance is dependent upon the combination of the angular velocity of said second member and the height of the first entrance above the second entrance when the moving means enters said first entrance.
 12. An apparatus accoRding to claim 2 and comprising: a. said second rotating member upon rotating in a first direction, said dog presents a leading surface and a trailing surface; b. with said moving means on said trailing edge of said stop and with said second rotating member rotating in said first direction, then said leading surface contacts said moving means to move said moving means away from said stop; c. with said moving means on said trailing edge of said stop and with said second rotating member rotating in a second direction, as opposed to said first direction, then said trailing surface contacts said moving means to force said moving means against said stop; d. with said moving means on said leading edge of said stop and with said second rotating member rotating in said first direction, then said leading surface contacts said moving means to force said moving means against said stop; and, e. with said moving means on said leading edge of said stop and with said second rotating member rotating in said second direction, then said trailing surface contacts said moving means to move said moving means away from said stop.
 13. An apparatus according to claim 12 and comprising: a. said dog being flexible.
 14. An apparatus according to claim 12 and comprising: a. said dog being flexible. b. said dog being more flexible in the vicinity of said leading surface than in the vicinity of said trailing surface; c. with said moving means on said trailing edge of said stop and with said second rotating member rotating in a second direction, then said trailing surface contacts said moving means to force said moving means against said stop and said dog deforms to pass over the combination of said moving means and said stop and to leave said moving means on said trailing edge of said stop; and, d. with said moving means on said leading edge of said stop and with said second rotating member rotating in a first direction, then said leading surface contacts said moving means to force said moving means against said stop to stop the rotation of said second rotating member with respect to said first member.
 15. An apparatus according to claim 1 and comprising: a. said dog and said second shoulder being integral.
 16. An apparatus according to claim 15 and comprising: a. said dog being flexible.
 17. An apparatus according to claim 3 and comprising: a. said dog and said second shoulder being integral; b. said dog being flexible; c. in the region of said leading edge there being a deformation in said dog to enhance the flexibility of said dog.
 18. An apparatus according to claim 12 and comprising: a. said dog and said second shoulder being integral.
 19. An apparatus according to claim 14 and comprising: a. in the region of said leading edge there being a deformation in said dog to enhance the flexibility of said dog.
 20. A winch comprising: a. a shaft; b. a first member; c. a second rotating member; d. said second rotating member being positioned on said shaft; e. said first member and said second member justapositioned to each other; f. on that part of the first member facing said second member there being a stop; g. on that part of the second facing said first member there being a first shoulder and a second shoulder; h. a moving means; i. said first shoulder and said second shoulder defining a first channel for said moving means; j. said first shoulder and said second shoulder defining a first entrance and a second entrance for said first channel; k. said first shoulder extending around part of said second shoulder; l. a dog on said second member; m. a third shoulder positioned on one of said members and facing the other one of said members and spaced apart from Said first shoulder; n. said first shoulder and said third shoulder defining a second channel; o. a first cam on said shaft; and, p. a second cam associated with said second rotating member and operatively positioned with respect to said first cam.
 21. A winch according to claim 20 and comprising: a. said second rotating member upon rotating at a slow speed in a first direction with said moving means on the trailing side of said stop, said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through said first channel and exits through said second entrance to move through said second channel to be on said trailing edge of said stop.
 22. A winch according to claim 20 and comprising: a. said second rotating member upon rotating at a fast speed in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through a portion of said first channel and exits through said first entrance to be on the leading edge of said stop so that upon the rotation of said second rotating member then said dog bears against said moving means which is on the leading edge of said stop so as to stop the rotation of said second rotating member.
 23. A winch according to claim 20 and comprising: a. said third shoulder being on said first member.
 24. A winch according to claim 20 and comprising: a. said third shoulder being on said second member.
 25. A winch according to claim 22 and comprising: a. a first cam on said shaft; b. said second rotating member having on a second face facing said first cam a second cam; and, c. when the rotation of said second rotating member stops and said shaft continues to rotate, said first cam bears against said second cam to force said second member toward said first member.
 26. An indicating apparatus, said apparatus comprising: a. a housing; b. said housing comprising a first shoulder, a second shoulder and a third shoulder; c. a moving means; d. said first shoulder and said second shoulder defining a first channel for said moving means; e. said first shoulder and said second shoulder defining a first entrance and a second entrance for said first channel; f. said first shoulder extending around part of said second shoulder; g. said housing comprising a dog; h. a third shoulder spaced apart from said first shoulder; i. said first shoulder and said third shoulder defining a second channel; j. an opening in said housing; k. a movable means; l. said movable means being partially outside said housing and projecting through said opening to be partially in said second channel; and, m. said movable means capable of moving to indicate a change in state.
 27. An apparatus according to claim 26 and comprising: a. said housing upon rotating at a slow speed in a first direction with said moving means on the trailing side of said movable means said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through said first channel and exits through said second entrance to move through said second channel to be on said trailing edge of said movable means.
 28. An apparatus according to claim 26 and comprising: a. said housing upon rotating at a fast speed in a first direction with said moving means on the trailing side of said movable means said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving meaNs moves through a portion of said first channel and exits through said first entrance to be on the leading edge of said movable means so that upon the rotation of said housing then said dog bears against said moving means which is on the leading edge of said movable means so as to move said movable means.
 29. An apparatus according to claim 26 and comprising: a. an electrical circuit; and, b. said movable means upon moving changing the state of said electrical circuit.
 30. An apparatus according to claim 26 and comprising: a. an indicator; and, b. said movable means upon moving contacting said indicator to change the state of said indicator.
 31. A method for controlling the rotation of a rotating second member in a combination of a first member and a rotating second member around a shaft, said method comprising: a. directing the movement of a movable means in a plurality of arcuate paths of travel around said shaft to assume a position with respect to a stop on said first member to allow said second member to rotate or to stop the rotation of said second member.
 32. A method according to claim 31 and comprising: a. the movement of said movable means being a function of the height of said movable means with respect to a first path of travel and a second path of travel.
 33. A method according to claim 31 and comprising: a. the movement of said movable means being a function of the angular velocity of said second member.
 34. A method according to claim 31 and comprising: a. the movement of said movable means being a function of the height of said movable means with respect to a first path of travel and a second path of travel and the angular velocity of said second member.
 35. A method according to claim 31 and comprising: a. The movement of said movable means being a function of the potential energy of said movable means with respect to a first path of travel and a second path of travel, and a function of the angular velocity of said second member.
 36. A powered platform comprising: a. a suspended scaffold; b. a winch connecting with said scaffold; c. said winch comprising a shaft; d. a first member; e. a second rotating member; f. said second rotating member being positioned on said shaft; g. said first member and said second member juxtapositioned to each other; h. on that part of the first member facing said second member there being a stop; i. on that part of the second member facing said first member there being a first shoulder and a second shoulder; j. a moving means; k. said first shoulder and said second shoulder defining a first channel for said moving means; l. said first shoulder and said second shoulder defining a first entrance and a second entrance for said first channel; m. said first shoulder extending around part of said second shoulder; n. a dog on said second member; o. a third shoulder positioned on one of said members and facing the other one of said members and spaced apart from said first shoulder; p. said first shoulder and said third shoulder defining a second channel; q. a first cam on said shaft; and, r. a second cam associated with said second rotating member and operatively positioned with respect to said first cam.
 37. A powered platform according to claim 36 and comprising: a. said second rotating member upon rotating at a slow speed in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through said first channel and exits through said second entrance to move through said second channel to be on said trailing edge of said stOp.
 38. A powered platform according to claim 36 and comprising: a. said second rotating member upon rotating at a fast speed in a first direction with said moving means on the trailing side of said stop said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through a portion of said first channel and exits through said first entrance to be on the leading edge of said stop so that upon the rotation of said second rotating member then said dog bears against said moving means which is on the leading edge of said stop so as to stop the rotation of said second rotating member.
 39. A powered platform according to claim 36 and comprising: a. said third shoulder being on said first member.
 40. A powered platform according to claim 36 and comprising: a. said third shoulder being on said second member.
 41. A powered platform according to claim 36 and comprising: a. a first cam on said shaft; b. said second rotating member having on a second face facing said first cam a second cam; and, c. when the rotation of said second rotating member stops and said shaft continues to rotate, said first cam bears against said second cam to force said second member toward said first member.
 42. A powered platform according to claim 36 and comprising: a. said winch being positioned above said scaffold and connecting with said scaffold by a cable suspension means.
 43. A powered platform according to calim 36 and comprising: a. said winch being positioned on said scaffold and being part of said scaffold.
 44. An indicating apparatus, said apparatus comprising: a. a first member; b. a second rotating member; c. said first member and said second member juxtapositioned to each other; d. an opening in said first member; e. a movable means; f. on that part of the second member facing said first member there being a first shoulder and a second shoulder; g. a moving means; h. said first shoulder and said second shoulder defining a first channel for said moving means; i. said first shoulder and said second shoulder defining a first entrance and a second entrance for said first channel; j. said first shoulder extending around part of said second shoulder; k. a dog on said second member; l. a third shoulder positioned on one of said members and facing the other one of said members; m. said first shoulder and said third shoulder defining a second channel; n. said movable means being partially outside said first member and projecting through said opening to be partially in said second channel; and, o. said movable means capable of moving to indicate a change in state.
 45. An apparatus according to claim 44 and comprising: a. said second rotating member upon rotating at a slow speed in a first direction with said moving means on the trailing side of said movable means said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through said first channel and exits through said second entrance to move through said second channel to be on said trailing edge of said movable means.
 46. An apparatus according to claim 44 and comprising: a. said second rotating member upon rotating at a fast speed in a first direction with said moving means on the trailing side of said movable means said dog engages said moving means and moves said moving means so as to enter said first channel through said first entrance; and, b. said moving means moves through a portion of said first channel and exits through said first entrance to be on the leading edge of said movable means so that upon the rotation of said seCond rotating member then said dog bears against said moving means which is on the leading edge of said movable means so as to move said movable means.
 47. An apparatus according to claim 44 and comprising: a. an electrical circuit; and, b. said movable means upon moving changing the state of said electrical circuit.
 48. An apparatus according to claim 44 and comprising: a. an indicator; and, b. said movable means upon moving contacting said indicator to change the state of said indicator.
 49. An apparatus, said apparatus comprising: a. a first member; b. a second rotating member; c. a shaft; d. a passageway in said first member; e. said shaft projecting through said passageway; f. said second rotating member mounted on said shaft; g. said first member and said second member juxtapositioned to each other; h. on that part of the first member facing said second member there being a stop; i. on that part of the second member facing said first member there being a first shoulder and a second shoulder; j. a first moving means; k. said first shoulder and said second shoulder defining a first channel for said first moving means; l. said first shoulder and said second shoulder defining a first entrance and a second entrance for said first channel; m. said first shoulder extending around part of said second shoulder; n. a dog on said second member; o. a third shoulder positioned on one of said members and facing the other one of said members and spaced apart from said first shoulder; p. said first shoulder and said third shoulder defining a second channel; q. a housing; r. said housing being mounted on said shaft; s. said housing comprising a fourth shoulder, a fifth shoulder and a sixth shoulder; t. a second moving means; u. said fourth shoulder and said fifth shoulder defining a third channel for said second moving means; v. said fourth shoulder and said fifth shoulder defining a first entrance and a second entrance for said third channel; w. said fourth shoulder extending around part of said fifth shoulder; x. said housing comprising a dog; y. a sixth shoulder spaced apart from said fourth shoulder; z. said fourth shoulder and said sixth shoulder defining a fourth channel; aa. an opening in said housing; bb. a movable means; cc. said movable means being partially outside said housing and projecting through said opening to be partially in said fourth channel; and, dd. said movable means capable of moving to indicate a change in state. 